Anti-corona antenna fittings



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Q N 'a S i S m I vo v ffl/mm..." s QM-w* i l gg Sg INVENTOR W/'///'am 0. Rogers BY @nel ATTORNEYS United States Patent() 3,154,634 ANTE-CURUNA ANTENNA FITTWGS William C. Rogers, 5365 NW. 36th St., Miami Springs, Fla.

Filed Feb. 6, 196i, Ser. No. 87,254 Claims. (Cl. l'74-3l'79) This invention pertains to fittings employed in antenna systems which operate under environmental conditions subjecting them to corona discharge effects.

Certain antenna installations, such as those for aircraft, have long been recognized as being vulnerable to the adverse effects of corona discharge resulting from highly charged atmospheric conditions. While concerted endeavors have been made to develop antenna fittings which would effectively minimize corona effects, such fittings have heretofore been characterized by a variety of structural and functional defects.

In the conventional prior art fittings, insulators usually of the ceramic variety, were incorporated with antenna wire holding and anchoring components. By virtue of the rigid and low tensile strength characteristics of ceramic materials, these structures tended to fail under the influence of wind induced vibration. The brittle nature of ceramics also made difficult the joining of insulator cornponents to anchor and antenna wire holding units. As a result, adhesive connections were employed which, with aging, tended to fail or separate.

Even with respect to antenna Wire holding components, difficulties have been encountered. lt was appreciated that a metallic cap afforded corona shielding and, if properly streamlined, tended to reduce fitting vibration. Despite this cognizance, however, only limited benefits were obtained through previously employed caps which terminated close to wire junctions.

It is with the elimination of the deficiencies and failings of previously employed, antenna fittings that this invention is concerned. It is the overall objective of the invention to provide antenna fittings affording maximum strength, minimum wind resistance, and yet which retain structural simplicity. j

It is a lparticular object of this invention to provide an antenna fitting of materially enhanced corona discharge shielding properties.

A further object is to embody, in an antenna fitting, an `improved interconnection between insulator member, wire connecting, and anchor components. Of particular concern is the provision for such connecting means which facilitate the interchangeability of components so as to achieve a versatility in fitting utilization hitherto unattained.

To accomplish the foregoing objects there are contemplated antenna fittings, each characterized by a slightly resilient insulator member having a body portion and at least one end portion of relatively reduced size on which are integrally formed compressible, threaded, male coupling means. For mounting on the insulator member there are provided antenna-wire receiving, electrically conductive cap means having a Wire receiving end and a smoothly merging barrel portion. The barrel portion is internally provided with threaded female coupling means for engaging the compressible, threaded, male coupling means of the insulator member end portion. Adjacent exterior portions of the barrel portion and the insulator member body portion are of the same configuration such that, with the insulator member end portion and the barrel portion threadably engaged, the barrel portion smoothly merges with the insulator member body portion.

In a preferred form of the invention wherein the antenna tting is to be employed as an antenna tensioning device, the cap means include an electrically conductive cap and a cap lcontinuation defining, electrically conducice tive, Wire adapter or holder. The cap is longitudinally bored to define an insulated-wire receiving bore, and has a wire receiving end and an adapter mandrel receiving cap barrel. The wire receiving end of the cap gradually enlarges from a relatively constricted terminus to smoothly merge with the cap barrel. The Wire adapter has, at one end, a wire holding mandrel and, contiguous with the mandrel at the other end of the adapter, an insulator member end portion receiving, adapter barrel.

The adapter barrel is exteriorly configurated to form a smooth, electrically conductive continuation ofthe cap barrel when the adapter mandrel is received within the cap barrel. To connect the insulator body and the cap and wire adapter assembly, an internal portion of the adapter barrel is provided with threaded, female coupling means for engaging the threaded, male coupling means of the insulator member end portion.

At the end of the insulator body opposite to that at which the wire adapter is connected, there may be connected an anchor unit. This anchor unit may comprise another antenna wire adapter and cap assembly as above described or, alternatively, aircraft connectable fittings not directly joined to an antenna wire.

Having described in general the structure of my invention, specific details thereof and the functional significance of fitting elements will now be explained in connection with preferred embodiments of the invention as illustrated in the accompanying drawings:

Referring to the drawings:

FIGURE 1 is a plan view of an aircraft in which an antenna is mounted by ttings of this invention;

FiGURE 2 is an enlarged side elevation of an insulated, antenna tensioning fitting shown installed in FIGURE l;

FIGURE 3v is a longitudinal section along the line 33-3 of FIGURE 2;

FIGURE 4 is an enlarged side elevation of a T-junction fitting shown installed in FIGURE l;

FIGURE 5 is a plan view of an insulator shell included in the T-junction fitting of FIGURE 4; and

FIGURE 6 is a sectional view along the line 6 6 of FIGURE 4.

In FIGURE 1 there is shown a conventional aircraft antenna installation. Antenna l, as illustrated, is tensionally supported by fittings including insulator unit 2 and an insulated tension unit 3.

The structural details of the insulated tension unit 3 are illustrated in FIGURES 2 and 3. The components of the unit include an insulator member 4, a wire adapter 5, a cap e, and an anchor unit '7. As shown in FIGURE 2, the unit is characterized by an elongate and streamlined exterior. To achieve this aerodynamically efficient configuration, all components of the unit are externally dimensioned so as to smoothly merge together.

Cap 6, fabricated from electrically conductive material, includes a longitudinally extending wire receiving bore S, a wire receiving end 9, and a cap barrel 10. The wire receiving end of the cap enlarges gradually from a relatively constricted terminus Il to smoothly merge with cap barrel lll. In the form of the invention illustrated, the interior of cap barrel lll is provided with coupling means of the threaded type.

Wire adapter S, also fabricated from electrically conductive material, includes a wire holding mandrel 12 extending from an adapter barrel 13. On wire holding mandrel l2, there are formed coupling means, in this case of the threaded type, to engage the threaded coupling means within cap barrel l0. However, it is to be appreciated that, while a threaded interconnection between mandrel l2 and barrel lll affords 'a particularly convenient and reliable coupling7 other coupling means may be utilized.

An insulated wire 14 received through wire receiving bore 8 of cap 6 is secured in mandrel 12 by a conventional transverse pin arrangement. In this arrangement, the end of wire 14 to be secured to mandrel 12 is formed into a small loop 15 and positionedwithin a longitudinal slot 16 in the end of mandrel 12 such that its opening is aligned with a bore 17 which extends transversely to slot 16. Through this bore a wire end securing pin 18 is passed to intersect the opening in loop 15.

Adapter barrel 13 is externally configured such that when cap 6 is assembled with adapter 5, by inserting adapter mandrel 12 into cap barrel 10, a smooth continuation of cap barrel 1li is defined. In the illustrated embodiment wherein barrels 10 and 13 are cylindrical, this is achieved merely by having both barrels of the same external diameter. While this sectional, wire receiving cap means construction is especially effective for certain installation requirements, unitary cap means may be employed, which also include an end adapted to receive an antenna wire and which smoothly merges with a barrel portion.

Insulator member 4 is uniquely fabricated so as to be possessed of high tensile strength, some limited resilience, and high electrically insulative or dielectric properties. A material possessing such properties is molded nylon. Molded nylon has sufficient tensile strength to enable the utilization of elongate insulator bodies considerably more slender than prior art insulator bodies fabricated from ceramics. This reduction in insulator member cross section, accompanied by a corresponding reduction in size of metallic fitting components, substantially minimizes the resistance offered by the fitting to air flow so as to cause less drag and Whip-lashing. This reduction in size also reduces the weight of the fitting and the cost of materials required in its fabrication. The resilience of nylon, although slight, is sufficient to reduce the likelihood of in sulator body failure under vibration stresses.

Insulator member 4 includes a body portion 19 and, at the end to which the adapter and cap assembly is to be secured, an end portion 20. End portion 2li is of reduced size relative to body portion 19 and has integrally formed on it threaded, male coupling means 21. By virtue of the resilience of the material from which insulator member 4 is formed, threaded coupling means 21 is longitudinally compressible in character.

An internal portion of adapter barrel 13 is provided with threaded female coupling means 22 adapted to engage threaded male coupling means 21 of insulator body 4. The compressible character of coupling means 21 causes the interconnection between coupling means 21 and 22 to be self-binding or separation resistant in character. As illustrated, with adapter barrel 13 and insulator member body portion 19, being of circular cross section configuration and of the same diameter, such that their abutting portions are identically configured, smooth merging of adapter 5 and insulator member 4 is insured.

At the end of insulator body 19 opposite to that at which wire adapter 5 is connected, there may be secured an anchor unit 7. The FIGURE 3 sectional view of anchor 7 discloses this unit as having a tensioning means including a coil spring 23. A plunger 24 is provided with an enlarged end 25 engaging the longitudinally movable, innermost end of coil spring 23. The opposite end of plunger 24 passes through the outermost, coil spring retaining end wall 26 of anchor unit 7 and terminates in an integrally formed eye 27. Through means of eye 27, the anchor unit 7 may be secured to an aircraft.

At the innermost end of anchor unit 7, there is mounted a longitudinally bored plug 28. Plug 28 is rigidly secured within the body of anchor unit 7 as by means of anchor unit body indentation 29 forced into an annular recess 31B on its exterior. Thus secured, plug 28 comprises means for retaining the spring tensioning means within the body of anchor unit 7.

The bore extending longitudinally inward from outer end of plug 26, and designated 31, is internally threaded.

This threaded female coupling means 32 engages a cylindrical end portion 33 of insulator member 4 which, like end portion 20, is provided with compressible, integrally formed, threaded male coupling means, in this case, designated 34. As with insulator member body 4 and wire adapter 5, the external configurations of adjacent and abutting portions of anchor unit 7 and insulator body 4 are identical so as to smoothly intermerge, with the merging in the illustrated embodiment resulting from equal diametered forms for body 4 and anchor unit 7.

While anchor unit 7 has been described as a tensioning unit, it may Well be only a solid unit provided with a cable eyelet or other aircraft connecting means. It will also readily be appreciated that the anchor unit may comprise an antenna wire adapter and cap assembly. A unit provided with such antenna Wire engaging means disposed at either end of an insulator member is shown installed as fitting 2 in FIGURE l.

To shield the junction of an antenna wire with a perpendicularly extending lead wire, an antenna fitting may Vbe employed embodying many of the structural and functional features incorporated in the previously described tension fittings. Such a fitting is shown in FIGURE 1 at the junction of antenna 1 and lead 35 and designated 36.

Fitting 36 as shown in FIGURE 4 is generally T-shaped and includes an insulator member 37 and three electrically conductive cap members 38 disposed individually at the terminal portions of the fitting.

As shown in the sectional view of FIGURE 6, insulator member 37 includes a pair of shells 39. Each shell, as shown in FIGURE 5, is T-shaped and on one side has a T-shaped channel 40. Extending from central shoulders 41 on body portion 42 of each shell 39 are semicylindrical terminal portions 43 upon each of which are integrally formed male, threaded coupling means 44. When placed in channel facing relationship, .shells 39 define an insulator member 37 to include a T-shaped internal bore, a central body portion, and externally threaded, cylindrical terminal portions of relatively reduced size.

Mounted on each terminal portion of the T-shaped insulator member 37 is a cap 38. In each such cap there is a longitudinally extending wire receiving bore 45, a wire receiving end 46, and a barrel portion 47. Wirereceiving end 46 gradually enlarges from a relatively constricted terminus 43 to smoothly merge with barrel portion 47.

Internally of barrel portion 47 there are formed threaded female coupling means 49 for engaging an externally threaded, cylindrical terminal portion of the insulator member. As the insulator shells are to be fabricated from a slightly resilient, dielectric such as nylon, the threaded coupling means on each cylindrical terminal portion is sufficiently compressible to cause a highly separation resistant coupling action. The outer surface of each cap 38 is configured to smoothly merge with the body portion of the insulator member when its barrel portion 47 is threadably engaged on a cylindrical, insulator member end portion.

To install fitting 36, insulator shells 39 are positioned on opposite sides of the junction of antenna 1 and lead 35. To secure the shells in this junction protecting relationship, caps 38 are assembled on antenna 1, on opposite ends of the junction, and on lead 35 and then advanced into threaded engagement with the insulator member terminal portions. When thus assembled, the antenna junction is effectively shielded without the imposition of strain by a fitting possessed of minimum aerodynamic resistance. The resilience of the insulator materially reduces the likelihood of its fracturing or failing due to vibration.

With antenna fitting structures of the type heretofore described, substantially improved fitting characteristics are obtained. Major advantages are attributable to the utilization of nylon as an insulator body material. The high tensile strength and slight resilience of nylon yields an insulator body of extreme structural durability. Despite exceptional tensile resistance, there is sufficient resilience in nylon to effectively absorb vibration caused by wind induced whip-lashing. The nylon resilience aiso provides an improved self-binding form of threaded connection, particularly important in relatively inaccessible antenna fittings.

The unique wire adapter is advantageous in several respects. lts exterior configuration is designed to conform to that of adjacent fitting components so as to reduce wind resistance. In defining a continuation of the cap barrel, the wire adapter barrel, in effect, elongates the cap to displace its inner terminal portion from the antenna and adapter mandrel junction and thus provides an unusually effective corona shield.

In employing threaded or equivalent connections between the insulator body and associated components such as wire adapters and anchors, a fitting characterized by unusual strength and versatility is obtained. The universal use of these connections facilitates the custom fabrication of fittings from basic components. Such connections are inherently possessed of greater tensile strength than mere adhesively secured pin fittings as known in the prior art. As will be readily appreciated, however, further strength and rigidity may be achieved by employing adhesives such as epoxy resins in these threaded connections.

Through the utilization of fitting components which are essentially of circular cross sectional configuration, a fitting of recognized aerodynamic efficiency results which may be fabricated with particular ease. Where appropriate, however, other streamlined fitting configurations may be employed.

The invention has been described with reference to specifically illustrated embodiments representative of its preferred form. However, as will be immediately obvious to those familiar with the antenna fitting art, modifications of the `disclosed structures may be effected which would be well Within the scope of my invention, which is defined in hte following claims.

I claim:

l. An antenna fitting comprising: an elongate, high tensile strength insulator having a body portion and an end portion of a relatively reduced size; said insulator comprising a solid, unitary member, with the outer periphery of the body portion of said insulator member defining a portion of the outer periphery of said antenna fittin; an electrically conductive wire adapter having a wire holding mandrel contiguous and integral with a relatively enlarged adapter barrel which receives said end portion; and an electrically conductive cap, said cap having a longitudinally extending wire receiving bore, a wire receiving end, and a cap barrel which receives said adapter mandrel; said adapter barrel being externally configured to form a smooth, electrically conductive continuation of said cap barrel beyond said mandrel when said mandrel is received within said cap barrel; the cross sections of adjacent portions of said cap barrel and said adapter and the cross sections of adjacent portions of said adapter barrel and said body portion of said insulator member having substantially the same outer peripheral configurations; said cap and said adapter forming an electrically conductive corona shield on the outer periphery of said fitting wherein said cap barrel and adapter barrel provide cylindrical portions extending axially in opposite directions from said wire holding mandrel with said wire receiving end of said cap cooperating with said cap barrel and said adapter to encase one end of an antenna wire received therein; said adapter including a male coupling portion facing toward said cap and received within and connected to said cap barrel, and said adapter barrel defining a female coupling portion facing toward said insulator member and receiving and connected with the end portion thereof, with said male and female coupling portions comprising integral portions of said adapter;

said cap barrel and said adapter barrel both being coaxial and opening away from said wire receiving end of said cap; and said cap and adapter defining an electrically conductive, corona shield carried by said end portion of said insulator member with said adapter barrel defining a cylindrical, electrically conductive, corona shield portion connecting the body portion of said insulator member and said wire holding mandrel in spaced relationship.

2. An antenna fitting according to claim l with said adapter barrel and said insulator member body portion being adapted to smoothly merge together when said adapter barrel and said insulator member end portion are engaged, said insulator member body portion being provided with a second end portion of reduced diameter, and an antenna anchoring unit having a barrel receiving and connected with said second end portion.

3. An antenna fitting according to claim 2 with said insulator member being constructed of a slightly resilient material; said end portions of said insulator member having integrally formed, compressible, threaded male coupling means; and said female coupling defined by said adapted barrel comprising threaded female coupling means engaging the compressible, threaded male coupling means of one end portion of said insulator member.

4. An antenna fitting comprising: an elongate, high tensile strength, insulator constructed of slightly resilient material having a body portion and end portions of relatively reduced size which define male coupling portions, said insulator comprising a solid, unitary member, with the outer periphery of the body portion of said insulator member defining a portion of the outer periphery of said antenna fitting; an electrically conductive wire adapter having a wire Vholding mandrel contiguous and integral with a relatively enlarged, adapter barrel which receives one of said insulator member end portions; an electrically conductive cap, said cap having a longitudinally extending wire receiving bore, a wire receiving end, and a cap barrel which receives said adapter mandrel, with said wire receiving end gradually enlarging from a relatively constricted terminus to smoothly merge with said barrel; said cap barrel and said adapter barrel being externally configured so as to smoothly merge together when said mandrel is received within said cap barrel; said cap and said adapter forming an electrically conductive corona shield on the outer periphery of said fitting wherein said cap barrel and adapter barrel provide cylindrical portions extending axially in opposite directions from said wire holding mandrel with said wire receiving end of said cap cooperating with said cap barrel and said adapter to encase one end of an antenna wire received therein; said adapter including a male coupling portion facing toward said cap land received within and connected to said cap barrel, and said adapter barrel defining a female coupling portion which faces toward said insulator member and which engages the male coupling portion defined by the one end portion of said insulator member, with said male and female coupling portions of said adapter comprising integral portions of said adapter; said cap barrel and said adapter barrel both being coaxial and opening away from said wire receiving end of said cap; said cap and adapter defining an electrically conductive, corona shield carried by said one end portion of said insulator member with said adapter barrel defining a cylindrical, electrically conductive, corona shield portion connecting the body portion of said insulator member and said wire holding mandrel in spaced relationship; said adapter barrel and said insulator member body portion being externally configured so as to smoothly merge together, when said adapter barrel and said one insulator member end portion are engaged; and an antenna tensioning, anchor unit having an anchor unit barrel receiving the other of said insulator member end portions; said anchor unit barrel having an internal portion provided with a female coupling portion engaging the male coupling portion of the other of said insulator member end portions, and adjacent portionsof said insulator member body portion and said anchor unit being externally of the same diameter so as to smoothly merge together, when said anchor unit barrel and said other insulator member end portion are engaged.

5. An antenna Viitting comprising: an elongate, high tensile strength insulator constructed of slightly resilient material having a bodyrportion and end portions of relatively reduced diameter on which are integrally formed compressible, threaded, male coupling portions, said insulator comprising a solid, unitary member, with the outer periphery of the body portion of said insulator member defining a portion of the outer periphery of said antenna fitting; an electrically conductive Wire adapter having a wire holding mandrel contiguous and integral With a relatively enlarged, vcylindrical adapter barrel which receives one of said insulator member end portions; an electrically conductive cap, said cap having a longitudinally extending Wire receiving bore, a Wire receiving end, and a cylindrical cap barrel which receives said adapter mandrel, with said Wire receiving end gradually enlarging from a relatively constricted terminus to smoothly merge with said barrel; said adapter barrel being externally diametered to conform to said cap barrel, whereby, with said adapter mandrel received Within said cap barrel, said adapter barrel forms 1a smooth, electrically conductive, cylindrical continuation of said cap barrel beyond said mandrel, said cap and said adapter thereby forming an electrically conductive corona shield on the outer periphery of said fitting wherein said cap barrel and adapter barrel provide cylindrical portions extending axially in opposite directions from said wire holding mandrel with said Wire receiving end of said cap cooperating With said cap barrel and said adapter to encase one end of an antenna Wire received therein; said adapter including a male coupling portion facing toward said cap and received VWithin and connected to said cap barrel, and said adapter barrel defining la female coupling portion which faces toward said insulator member and which engages the compressible male coupling portion defined by the one portion of said insulator member, With said male andv female coupling portions vof saidadapter comprising integral portions of said adapter; said cap barrel and said adapter barrel Vboth being coaxial 'and opening away from said Wire receivingrend of said cap; said cap and adapter defining an electrically conductive, corona shield carried by said one end of said insulator member with said adapter barrel deining a cylindrical, electrically conductive, corona shield. portion connecting the body portion of said insulator member and said kwire holding mandrel in spaced relationship; said adapter barrel and said insulator member body portion being externally of the same general diameter so as to smoothly merge together when said adapter barrel and said one insulator member end portion are threadably engaged; and an antenna tensioning, anchor unit in which are contained antenna tensioning means and retaining means for said ten- Vsioning means; said retaining means including a plug received within and connected to one end of said anchor unit and havingY an outwardly facing, longitudinally bored, insulator member end portion receiving barrel and Van inwardly facing tensioning means abutment; said retaining means barrel having an internally threaded female coupling portion engaging the compressible, theaded, male coupling portion of the other of said insulator member end portions; and said insulator member body portion and said anchor unit being externally of the same general diameter so as to smoothly merge together when said retaining means barrel and saidother insulator member end portion are engaged. l'

References Cited by the Examiner UNITED STATES PATENTS 1,238,885 9/17 Chmela 174--92 2,434,658 U48 Katz 174l77 X 2,535,072 12/50 Katz 174-75 2,705,255 3/55 Slaughter et lal 174-179 2,705,256 3/55 McGee 174-179 JOHN F. BURNS, Primary Examiner.

BENNETT G. MILLER, IOHN P. WILDMAN,

Examiners. 

1. AN ANTENNA FITTING COMPRISING: AN ELONGATE, HIGH TENSILE STRENGTH INSULATOR HAVING A BODY PORTION AND AN END PORTION OF A RELATIVELY REDUCED SIZE; SAID INSULATOR COMPRISING A SOLID, UNITARY MEMBER, WITH THE OUTER PERIPHERY OF THE BODY PORTION OF SAID INSULATOR MEMBER DEFINING A PORTION OF THE OUTER PERIPHERY OF SAID ANTENNA FITTING; AN ELECTRICALLY CONDUCTIVE WIRE ADAPTER HAVING A WIRE HOLDING MANDREL CONTIGUOUS AND INTEGRAL WITH A RELATIVELY ENLARGED ADAPTER BARREL WHICH RECEIVES SAID END PORTION; AND AN ELECTRICALLY CONDUCTIVE CAP, SAID CAP HAVING A LONGITUDINALLY EXTENDING WIRE RECEIVING, BORE, A WIRE RECEIVING END, AND A CAP BARREL WHICH RECEIVES SAID ADAPTER MANDREL; SAID ADAPTER BARREL BEING EXTERNALLY CONFIGURED TO FORM A SMOOTH, ELECTRICALLY CONDUCTIVE CONTINUATION OF SAID CAP BARREL BEYOND SAID MANDREL WHEN SAID MANDREL IS RECEIVED WITHIN SAID CAP BARREL; THE CROSS SECTIONS OF ADJACENT PORTIONS OF SAID CAP BARREL AND SAID ADAPTER AND THE CROSS SECTIONS OF ADJACENT PORTIONS OF SAID ADAPTER BARREL AND SAID BODY PORTION OF SAID INSULATOR MEMBER HAVING SUBSTANTIALLY THE SAME OUTER PERIPHERAL CONFIGURATIONS; SAID CAP AND SAID ADAPTER FORMING AN ELECTRICALLY CONDUCTIVE CORONA SHIELD ON THE OUTER PERIPHERY OF SAID FITTING WHEREIN SAID CAP BARREL AND ADAPTER BARREL PROVIDE CYLINDRICAL PORTIONS EXTENDING AXIALLY IN OPPOSITE DIRECTIONS FROM SAID WIRE HOLDING MANDREL WITH SAID WIRE RECEIVING END OF SAID CAP COOPERATING WITH SAID CAP BARREL AND SAID ADAPTER TO ENCASE ONE END OF AN ANTENNA WIRE RECEIVED THEREIN; SAID ADAPTER INCLUDING A MALE COUPLING PORTION FACING TOWARD SAID CAP AND RECEIVED WITHIN AND CONNECTED TO SAID CAP BARREL, AND SAID ADAPTER BARREL DEFINING A FEMALE COUPLING PORTION FACING TOWARD SAID INSULATOR MEMBER AND RECEIVING AND CONNECTED WITH THE END PORTION THEREOF, WITH SAID MALE AND FEMALE COUPLING PORTIONS COMPRISING INTEGRAL PORTIONS OF SAID ADAPTER; SAID CAP BARREL AND SAID ADAPTER BARREL BOTH BEING COAXIAL AND OPENING AWAY FROM SAID WIRE RECEIVING END OF SAID CAP; AND SAID CAP AND ADAPTER DEFINING AN ELECTRICALLY CONDUCTIVE, CORONA SHIELD CARRIED BY SAID END PORTION OF SAID INSULATOR MEMBER WITH SAID ADAPTER BARREL DEFINING A CYLINDRICAL, ELECTRICALLY CONDUCTIVE, CORONA SHIELD PORTION CONNECTING THE BODY PORTION OF SAID INSULATOR MEMBER AND SAID WIRE HOLDING MANDREL IN SPACED RELATIONSHIP. 